Offline transactions / Hardware WALLΞTH

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WALLETH 0.14 is about “offline transactions”. This is a security feature - a bit like a hardware wallet. The Idea is that you have WALLETH on 2 separate phones:

  • One phone (e.g. your daily driver) has Internet access and some account in watch-only mode
  • Another phone (e.g. an old phone where you perhaps even removed the GSM and WIFI antennas) has no Internet access and holds the key for the account

You prepare the transaction on the first phone. In the transaction-details you see then a QR-Code with the unsigned RLP. With the other phone you scan this code & sign the transaction. This phone then shows you an QR-Code with the “signed RLP”. Yes this is a bit of ugly QR-Code juggling - but it also has nice properties:

  • cheap - you might have this old phone in your drawer but would need to buy a hardware wallet
  • you can visually inspect the very restricted communication. You can e.g. see if a QR-Code contains a lot of data or not (by the size of the dots) - also you are clearly aware of the direction of communications. With hardware wallets you cannot see easily which data is exchanged on the wire between the hardware-wallet and the internet-connected and untrusted device.

You can later even combine this feature with hardware wallets for very sensitive accounts/use-cases. I am currently preparing TREZOR support in WALLETH. If you want to have a peek behind the curtains: relevant PullRequests & relevant issues

Currently only WALLETH<>WALLETH is supported. But as soon as this issue with the geth mobile API is solved the offline part can also be done with MyEtherWallet.